My 11 year old daughter needed a tow back to shore last time we went out at Henly lake, Masterton.
The wind was blowing her Ocean kayak Venus 11 (non ruddered) sideways and she couldn't make enough headway to turn at the same time.

I thought that giving the Venus 11 (and daughter) a boost would be a good idea.
I didn't want to go to a full-on trolling motor as the amperage needed to drive them seem to require a fairly big battery. Besides, all that power might go to her head and we can't have her outdistancing her father, it's bad for his ego.

Currently it is set up to only go forward, with steering provided by the paddle.

I have picked up a couple of old TMC 2000 bilge pumps that I have never used and had an old propeller that I used when I was dabbling with a weed eater outboard back in the Aqua 2 days, I wound up not going down that path (too noisy and not in keeping with the corporate image) but the propeller that I used was still sitting around.

I started of with a rudder hinge, I've mounted it the wrong way around on the kayak... this allows the motor to be pulled out of the water when in the shallows. I have attached it to a old extendable aluminium tent pole as a shaft.

I have attached a rope that goes forward, it locks the motor out of the water.

I removed the impellor of the bilge pump and cut the plastic housing, leaving the motor sealed inside the waterproof housing and bolted it to the shaft.

The prop is a Young's T-10 (5.75" diameter) that I imported years ago, but still available... I drilled out the hole all the way through.
The shaft is an extension bit for a battery drill, it comes with a thread and the prop just threaded itself onto that.

The motor runs (on land) at 2 - 2.5 Amps... so in theory it would give nine hours run time on a single 12v 18 amp-hour battery if I were to suck it dry (not that I would.)

Currently I'm going with a foot operated control... a simple press button that stops the motor when it is released. Full speed only!

I've tried it out on my Reload, it seemed to be giving a good walking pace... I'm fairly happy with that, considering what it's made out of.

I hope to get it out and take a video when the weather is good and see if I can get a proper speed reading on it.

If the battery does last long enough, I might get a bigger pump and a larger prop and see what that can do.

Just something on the amp draw, it will increase drastically under load. Looks fairly calm where you are and your daughter certainly does not add much weight to the equation. With my weight though and the conditions I tend to encounter on the ocean up here, I doubt 18AH at 5kph would last me more than 2 hours.

Yep, thanks for that.
I had thoughts of being able to swap it between the Venus 11 and my Reload.
If I did that I would add a few more batteries, in parallel, to increase the Amp-hours/run-time.

I might put the ammeter back on and see what it draws, on the water, to get a better idea of what it is using under load.
The info stamped on the pump says 10 Amps... but that seems too much when the pump doesn't seem to be struggling to move at 5kph.

I took it out on the water, with a 10 Amp fuse. Started it up and... blew the fuse (taking out the power to the fish finder for the duration of the trip.)

I thought I had better check it out properly...

I set the motor up in a bucket to check what Amp's it draws under load...

And hooked up my analogue Ammeter...

Oh... I wasn't expecting that!

Digital meter...

So... lots more than I thought.

Good news/bad news...
Its more powerful than I thought it would be / less Amperage than even the smallest commercial trolling motor. Thats not a really a bad thing, as it's just an aid for my daughter.